I did the same thing for 100+ some workstations. If you don't have several OUs in your AD structure, it might be a little more difficult, but I would do exactly what Mart suggested and just create a batch file and put it in a startup script to call the setup.exe.

If you have different locations, it might be smart to copy the files to the different locations as it would take forever to do the install over a WAN. Then create a kix script to run the install depending on what IP address the workstation is at.